The letters of notification follow similar communication early this week to Google Inc. and its subsidiary YouTube from the Jersey City, N.J.-based mobile solutions company, according to the Silicon Valley/San Jose Business Journal.

The company also sent a letter to cloud content services provider Brightcove Inc.

“Our patent portfolio is a valuable component of our business," said Anthony Macaluso, Single Touch’s chairman and chief innovation officer, in a statement, "and we will not waiver in protecting our intellectual property.”